Auhonso comstock pratt



A. C. PRATT.

BEAD CABLE FOR AUTOMOBILE TIRES.

APPLICATION FILED JAN.20. 1921.

1,386,072. Patented Aug. 2,1921.

UNITED STATES,

PATENT orrica.

READ-CABLE FOR AUTOMOBILE-TIRES.

Specification of Letters Patent.

Patented Aug. 2, 1921.

Application filed January 20, 1921. Serial No. 438,577.

To all whom it may concern:

Be it known that I, ALrHoNso COMSTOCK PRATT, a citizen of the United States, residmg at Deep River, in the county of Middlesex, State of Connecticut, have invented cernected from it, the casing being formed of a I plurality of'convolutions of spirally formed wire with the spirals of the several convolutions' lying side by side'around the core. Such a bead cable can be made at relatively low cost, particularly when the casing is made of preformed wire, that is, wire which is bent to its spiral configuration before it is applied to the core. Also, with a bead cable constructed in this manner, the casing being wholly disconnected from the core, may turn more or less about the core during the process ofmanufacturinga casing without any change in the relation of the several convolutions constituting the casing, such as would cause bursting strains on the bead cable to be assumed unequally by the several convolutions. This is of special advantage in connection with. certain processes of manufacturing automobile tires.

The core for a bead cable constructed in accordance with the invention preferably consists of a single piece of wire of the requisite diameter which is bent to a circle and has its ends joined together in any suitable manner as by welding, so as to form a hoop which is of uniform cross section at all points.

The casing of convolutions of spirals is applied to this core without permanently connecting it to the core. If desired, the end of the wire from which the casing is formed may be temporarily attached to the core to facilitate the process of spiraling the wire, but if so, it is subsequently disconnected from the core. Preferably the wire for the casing is not attached to the core at any time. Instead, the wire is preformed by giving it its spiral configuration before it is applied to the core. This may be done by the employment of a winding machine of the type illustrated and described in Patent-No. 1,294,160 granted to me on February 11, 1919. In such a machine, the wire for the casing is fed through a spirally formed die so that the wiring issuing from the die is in the form of a succession of spirals and the wire thus formed is laid upon the core to form a plurality of convolutions of spirals inclosing the core with the spirals of the several convolutions lying side by side. To do this, the previously formed hoop constituting the core is placed in the winding machine and a separate wire is fed through the die of the machine to spiral the wire and then lay it upon the core. The grip of the spirals of the spirally formed casing wire is quite suflicient to carry the core around in the guide or holder for the bead cable being formed after the first spiral or two have been applied to the wire. Preferably the casing of convolutions of spirals consists of six convolutions. When the desired number of convolutions of spirals have been applied to the core, the wire from which the casing is formed is cut at such a point that when the end of the wire where the cut is made is applied to the cable, it will abut against the other end of the casing wire. These two ends may be joined together in any suitable manner as by welding them, but such connection of the ends of the casing wire is unnecessary. Even if the ends of the casing wire are not joined, a bursting strain imposed upon the cable will not cause these ends to be raised from the cable as the strain on the convolutions of spirals will cause them to grip the core the more tightly.

The preferred embodiment of the invention is illustrated in the accompanying drawings in which Figure 1 is a view of the core; Fig. 2 is a View of the completed cable; Fig. 3 is a view on enlarged scale of a portion of the cable shown in Fig. 2, and Fig. 4 is a cross-section on line 4 4 of Fig. 8.

Referring to these drawings, Fig. 1 shows the core formed from a single piece of wire bent to clrcular form and having its ends welded together as shown at 2.

The casing 3 of convolutions of spirals is applied to this core 1, six convolutions of spirals being employed preferably and these being arranged in the manner indicated 111 Figs. 3 and 4. The wire for the conv0lutions of spirals may be wound spirally un' der tension upon the core 1 but preferably the wire is preformed so as to give it its spiral configuration before it is applied to the core. The ends of the wire from which the casing is formed abut as is shown at 4c and these ends may be welded together or may remain disconnected as desired;

It will be noted that the cable constructed as above described consists of two pieces of wire, one forming the core and the other forming a casing inclosing the core but wholly disconnected from it. Because of this characteristic of the construction, the casing as a whole is free to be moved angularly more or less about the core and since each convolution of the casing is a succession of similar spirals throughout its length, any such angular movement of the casing about the core will not effect any change in the relative lengths of the several convolutions. Therefore, a bursting strain imposed upon the cable will be resisted equally by all of the convolutions of spirals irrespec tive of whether or not there has been any angular movement of the casing about the core. This characteristic of the cable is of special value in tire casings which are made initially in the form 01 a flat band and their expanded or distended throughout the central portion of the band to cause the band to assume the configuration of a tire casing.

In such shaping of a flat band to the form of a casing, the edge portions of the band which form the bead of the cable, turn through an angle approximating 90 and during this angular movement of the beads, the casings of the cables may turn more or less upon their cores, and the casings in their new relation will be capable of withstanding the strains to which the beads of the casing are subjected without any distribution of the strain upon the several convolutions of the cable. As stated above, the ends 4: of the wire for the casing need not be joined together. The imposition of a bursting strain upon the cable will not cause these ends to rise from their positions. Nevertheless, it may be desirable to secure the ends of the casing wire in some manner so as to prevent them from being raised from their positions accidentally. These ends may be welded together or they may be secured in position by solder or a band of sheet metal may be laid around the cable overlying the ends 4 ot the casing wire and the ends of this sheet metal band may be secured together in any suitable manner.

I claim:

1. A head cable comprising the combination of a core and a casing on the core consisting of a plurality of convolutions of spirals with the spirals of the several convolutions lying side by side, the core and the casing being wholly disconnected one from the other so that the casing as a whole may move angularly upon the core.

2. A bead-cable comprising the combination of a core and a casing on the core con.- sisting of a plurality of convolutions ot spirals with thespirals of the several convolutions lying side by side, the casing being wholly disconnected from the core and having the ends of the piece of wire from which it is formed abutting.

A head cable formed from two pieces oi wire one constituting a core and having its ends welded together to form a hoop and. the other constituting a casing consisting of a plurality of convolutions 0t spirals with the spirals of the several convolutions lying side by side about the core, the casing being disconnected from the core and having the ends of the piece of wire from which it is formed abutting.

In testimony whereof I aflix my signature.

ALPHONSO COMSTOCK PRATT. 

